Glass pressing machine



P 1936- A. H. LE MARE ,40

GLASS PRESSING MACHINE Filed April 28, 1934 Patented Sept. 8, 1936 2,053,402 I GLASS rms's'smc MACHINE Alfred Henry Le Mare; St. Helens; England, assignor to Pilkington BrothersfLimited, Liver- England, a company duly registered d r th Limit d. Liability. .Co nina y Acts I of I England Application-April 28, 1934, .Serial No. 722,898

In Germany May .15, 1933 1 Claim. (01, e snj This invention relates to glass forming ma-.'

chines of the type in whicha-forming plunger is mechanically forced into the moltenglass and has for its object an improved apparatus for.

actuation of the plunger.

According to the invention the forming plunger is actuated by a cam so formed thatafter the plunger has been forced into the molten glass. to the point at whichthe desired form has been. given to the glass, it is withdrawn to a very slight extent. It is then held stationary in this slightly withdrawn position for a certain time and is then withdrawn completely. Preferably the cam is formed in two portions, of which one is adjustable relatively to the other, so as to adjust the time during which the plunger is held in its slightly withdrawn position.

When a plunger is maintained in the position to which, it has been forced into the glass, it is liable to adhere to the glass, this liability depending on the shape of the plunger and the degree to which it becomes heated. On the other hand, if the plunger be immediately withdrawn, the glass, which is then still very soft, is liable to deform.

By means of the present invention, the advantage is secured of avoiding adherence of the glass to the plunger, since this adherence does not occur with incomplete contact between glass-and plunger, and at the same time of maintaining accuracy of form of the glass.

The time during which the plunger should be held in the slightly withdrawn position to avoid deformation of the glass, depends on the shape and mass of the glass pressing. By means of the above described adjustable cam device, this time can be adjusted to that best adapted to any article being pressed.

In the accompanying drawing:--

Figure 1 is a side elevation of the main portions of a pressing machine with two plungers, the cam device and upper portion of one plunger rod being shown in section, and

Figure 2 is an approximate plan view from below of the cam device.

Referring to the drawing which shows a pressing machine to which the invention is applied, a central fixed shaft I is the support for all portions of the machine. The framework 2 comprising the mould table 3 and the plunger guides 4, is rotated about the shaft I by means of the gear wheel 5. The cam casing 6 is fixed to the shaft I, and contains the fixed cam I, 8 and the movable cam 9, ID. The plungers II are attached to rods I2 passing through guides 4. On the upper ends of each'of the rods I2 are two nuts I3, I I, the lower nuts I3 serving as'adjustable abutments for the springs: -I5. The upper ends of thesprings I 5 bear against sleeves I6 to which are pivoted at I! links I8, connecting the sleeves toarms I9 of two-armedlevers I9, 2| pivoted at 7 28; to the framework 2. The other arms 2| of the levers carry each two rollers 22, 23 engaging the fixed and movable cams I, 8 and'9, I respectively. 1 I

At, the left hand side of Figure 1, the plunger II is shown in its fully withdrawn position and at the right hand side in the lowest position to which it is forced.

By rotation of the framework 2 relatively to the fixed cam casing 6, the levers I9, 2| are actuated, first to depress the sleeves I6, the pressure thereon being transmitted through the springs I to the nuts I3 on the plunger rods I2. The springs i5 are stiff enough to transmit the pressure without relative movement of the sleeves I6 and the rods I2, except at the end of the stroke, when the sleeves make a small movement relatively to the rods, whereby the final pressure applied to the plungers is determined by the stiffness of the springs I5. This small movement is indicated at the right hand side of Figure 1 by the gap between the upper end of the sleeve I6 and the nut I4.

Immediately after theplungers have reached their lowest position, the levers I9, 2I are moved by the cams sufficiently to raise the sleeves I6 into contact with the nuts I 4 and a very small further distance, so as to withdraw the plungers by a very small extent; I

The levers then remain in this position to hold the plungers in their slightly withdrawn position for the time determined by the cams and then are moved to raise the plungers into the fully withdrawn position as shown on the left hand of Figure 1.

Figure 2 is an approximate plan view from below of the cam casing 6 with the cams, to a scale one-third larger than that of Figure 1. It departs from an accurate plan view in showing the cam surfaces of the fixed and movable cams coincident when both hold the lever arms ZI in the same position, thus showing the action of the cam surfaces more clearly. Actually the cam surfaces are not so coincident by reason of the angular positions of the lever arms 2|. The fixed cam members I, 8 and the roller 22 engaging them, are shown in full lines and the movable cam members 9, III and the roller 23 engaging them in dotted. lines. In this figure,

cate a part that is covered by another part. subject to the above, the cam casing in Figure 1 is a section along the line A--A of Figure 2,

The two members I, 8 of the fixed cam are keyed at '24 and 25. respectively to the casing 6, and are retained therein by the plate 35 (omitted in Figure 2). The twomembers 9, ID

of the movable cam are fixed to the plate 28, which is held to the casing 6 by bolts 21;(Fig-- ure 1) passing through circular slots in' the casing, whereby the plate 26 with the cam members 9, I can be rotated and-fixed in any desired angular position relatively to the-casing;

The action of the cam surfaces is as rollowsz- Starting with the roller 22 in the position of 28 (Figure 2) corresponding to thegiully withdrawn position of the plunger as on. the lelt hand side of Figure 1, the roller moves (counterclockwise in Figure 2) in a circular path to the position 29. From here to" the position 30 it is moved by the. fixed cam member 8 to give the downward stroke of the plunger, this reaching its lowest position at 30, corresponding to the position shown at the right hand side of Figure 1. Immediately after, it is moved to the position at 3| to efiect the very slight withdrawal of the plunger. It; then moves in a circular path between the fixed cam members I, 8 maintaining the plunger in its slightly Withdrawn position, as far as the position at 32. This length plunger fully;

From the above it will be seen that, by rotating the movable cam members 9, I 0 relatively to the fixed cam members, the length of the circular path, during which the plunger is held in its slightly withdrawn position, may be varied from the minimum length between positions 3| and 3.2, determined. by the fixed cam members, to a length approximately double.

Having described my invention, I declare that what'I claim and desire to secure by Letters Patent is:--

Apparatus for pressing glass articles comprising in combination a forming plunger, a cam surface adapted to press the plunger downwards to form the article, a second cam surface adapted to withdraw the plunger slightly, a third cam surface adapted to hold the plunger in the slightly withdrawn position and afourth cam'surface adapted to withdraw the plunger fully.

ALFRED HENRY LE MARE. 

